Enzymes are used industrially for many purposes, including the hydrolysis of starch, the breakdown of protein, and the isomerization of glucose to fructose. For years this use has involved soluble enzyme, which is lost after one use. In the past five years there has arisen a new industrial use of the technology in which enzymes are immobilized, usually to a solid material. This allows many uses of the enzyme and leads to greater economy.
The chief methods of immobilization are adsorption, covalent bonding, entrapment in a polymer, and entrapment inside the cell membrane. With respect to the prior art a group of patents have been heretofore issued in Italy and Germany to D. Dinelli, and assigned to SNAM Progetti and are directed to the entrapment of enzymatically active materials in cellulose acetate. This group of patents, however, appears not to involve second solid phases added to the formulation and further appears not to involve subsequent swelling after formation of a solvent not completely aqueous. It is therefore felt that the prior art has not completely solved the problems in this area, at least not for all intended applications.